RESUMEN
Polycyclic Aromatic Hydrocarbons (PAHs) are organic compounds with two or more condensed aromatic rings, formed from incomplete organic matter combustion. PAHs pose potential health risks due to their carcinogenic and mutagenic properties, accumulating in edible tissues of aquatic organisms, such as shrimp, which is extensively produced in the southern region of Rio Grande do Sul state (Brazil) and it is the most consumed seafood globally. Therefore, this study aimed to optimize and validate an analytical method for extracting 16 priority PAHs from shrimp samples using Vortex-Assisted Matrix Solid-Phase Dispersion (VA-MSPD) with determination by Gas Chromatography Tandem Mass Spectrometry (GC-MS/MS). The optimized method, which uses a reused solid support, was validated according to INMETRO and SANTE guidelines. PAHs demonstrated adequate linearity with correlation coefficients > 0.99. The matrix effect was assessed, and 12 out of the 16 PAHs showed a matrix effect of less than ±20%. The method's quantification limits ranged from 6.67 to 33.35 ng g-1. Accuracy and precision showed recovery values ranging from 55 to 115% with relative standard deviation (RSD) lower than 17% for all PAHs. In the applicability, 11 PAHs were detected, such as benzo[a]pyrene and benzo[b]fluoranthene, and the ∑PAHs ranged from 25.14 to 79.52 ng g-1, confirming the environmental contamination in the region and the need for monitoring these contaminants in shrimp destined for human consumption.
Asunto(s)
Cromatografía de Gases y Espectrometría de Masas , Penaeidae , Hidrocarburos Policíclicos Aromáticos , Extracción en Fase Sólida , Espectrometría de Masas en Tándem , Hidrocarburos Policíclicos Aromáticos/análisis , Hidrocarburos Policíclicos Aromáticos/aislamiento & purificación , Animales , Cromatografía de Gases y Espectrometría de Masas/métodos , Espectrometría de Masas en Tándem/métodos , Extracción en Fase Sólida/métodos , Penaeidae/química , Límite de Detección , Brasil , Alimentos Marinos/análisis , Contaminación de Alimentos/análisis , Reproducibilidad de los Resultados , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificaciónRESUMEN
In this study, lignin derived from corncobs was chemically modified by substituting the hydroxyl groups present in its structure with methacrylate groups through a catalytic reaction using methacrylic anhydride, resulting in methacrylated lignin (ML). These MLs were incorporated in polymerization reaction of the monomer 2-[(acryloyloxy)ethyl trimethylammonium] chloride (Cl-AETA) and Cl-AETA, Cl-AETA/ML polymers were obtained, characterized (spectroscopic, thermal and microscopic analysis), and evaluated for removing Cr (VI) and As (V) from aqueous media in function of pH, contact time, initial metal concentrations and adsorbent amount. The Cl-AETA/ML polymers followed the Langmuir adsorption model for the evaluated metal anions and were able to remove up to 91 % of Cr (VI) with a qmax (maximum adsorption capacity) of 201 mg/g, while for As (V), up to 60 % could be removed with a qmax of 58 mg/g. The results demonstrate that simple modifications in lignin enhance its functionalization and properties, making it suitable for removing contaminants from aqueous media, showing promising results for potential future applications.
Asunto(s)
Cromo , Lignina , Contaminantes Químicos del Agua , Lignina/química , Cromo/química , Cromo/aislamiento & purificación , Adsorción , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Polímeros/química , Polímeros/síntesis química , Agua/química , Concentración de Iones de Hidrógeno , PolimerizacionRESUMEN
Orange II, an azo dye used in textile and leather industries, is toxic and contributes to reducing dissolved oxygen in water. In this sense, agri-food waste adsorbents offer efficient, cost-effective dye removal. In this study, potato surpluses were evaluated as adsorbents for the removal of Orange II at 22 °C and pH values between 4 and 9. The adsorbents were characterized by their morphology, elemental composition, infrared spectra, and point of zero charge. Adsorption isotherms were analysed using Langmuir and Freundlich models, revealing that the Langmuir equation (0.933 < r2 > 0.882) better described the adsorption process compared to the Freundlich model (0.909 < r2 > 0.852). The maximum adsorption capacity at pH 4 was 1.1 and 2.3 times higher than at pH 7 and 9, respectively. This increased capacity at pH 4 was due to favourable electrostatic interactions between the cationic adsorbent surface and the anionic dye. A kinetic model was developed to understand the adsorption dynamics of Orange II, demonstrating high accuracy with coefficients of determination (r2) exceeding 0.99 across various pH values. The predictions of the kinetic model aligned well with the Langmuir isotherm results, indicating a strong theoretical foundation. The critical contact time required to achieve the minimum adsorbent concentration necessary for meeting a discharge limit of 14.7 mg L-1 was determined using both the Langmuir and kinetic models. Simulation profiles showed that when the adsorbent concentration was increased from 12 to 40 g L-1, the contact time necessary to achieve the discharge limit decreased from 26 to 3.35 h, highlighting the trade-off between contact time and cost. This study offers a cost-effective solution for wastewater treatment and presents a robust model for optimizing batch adsorption processes, marking a significant advancement in using potato surpluses for dye removal.
Asunto(s)
Compuestos Azo , Bencenosulfonatos , Solanum tuberosum , Contaminantes Químicos del Agua , Purificación del Agua , Solanum tuberosum/química , Compuestos Azo/química , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Bencenosulfonatos/química , Purificación del Agua/métodos , Colorantes/químicaRESUMEN
The present work describes a quick, simple, and efficient method based on the use of layered double hydroxides (LDH) coupled to dispersive solid phase micro-extraction (DSPME) to remove α-naphthol (α-NAP) and ß-naphthol (ß-NAP) isomers from water samples. Three different LDHs (MgAl-LDH, NiAl-LDH, and CoAl-LDH) were used to study how the interlayer anion and molar ratio affected the removal performance. The critical factors in the DSPME procedure (pH, LDH amount, contact time) were optimized by the univariate method under the optimal conditions: pH, 4-8; LDH amount, 5 mg; and contact time, 2.5 min. The method can be successfully applied in real sample waters, removing NAP isomers even in ultra-trace concentrations. The large volume sample stacking (LVSS-CE) technique provides limits of detections (LODs) of 5.52 µg/L and 6.36 µg/L for α-naphthol and ß-naphthol, respectively. The methodology's precision was evaluated on intra- and inter-day repeatability, with %RSD less than 10% in all cases. The MgAl/Cl--LDH selectivity was tested in the presence of phenol and bisphenol A, with a removal rate of >92.80%. The elution tests suggest that the LDH MgAl/Cl--LDH could be suitable for pre-concentration of α-naphthol and ß-naphthol in future works.
Asunto(s)
Electroforesis Capilar , Límite de Detección , Naftoles , Microextracción en Fase Sólida , Contaminantes Químicos del Agua , Naftoles/química , Naftoles/análisis , Naftoles/aislamiento & purificación , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificación , Contaminantes Químicos del Agua/química , Electroforesis Capilar/métodos , Microextracción en Fase Sólida/métodos , Hidróxidos/química , Isomerismo , Reproducibilidad de los Resultados , Concentración de Iones de HidrógenoRESUMEN
The purpose of this research was to evaluate the efficacy of sodium lignosulfonate (LS) as a dye adsorbent in the removal of methylene blue (MB) from water by polymer-enhanced ultrafiltration. Various parameters were evaluated, such as membrane molecular weight cut-off, pH, LS dose, MB concentration, applied pressure, and the effect of interfering ions. The results showed that the use of LS generated a significant increase in MB removal, reaching an elimination of up to 98.0 % with 50.0 mg LS and 100 mg L-1 MB. The maximum MB removal capacity was 21 g g-1 using the enrichment method. In addition, LS was reusable for up to four consecutive cycles of dye removal-elution. The removal test in a simulated liquid industrial waste from the textile industry was also effective, with a MB removal of 97.2 %. These findings indicate that LS is highly effective in removing high concentrations of MB dye, suggesting new prospects for its application in water treatment processes.
Asunto(s)
Lignina , Azul de Metileno , Ultrafiltración , Contaminantes Químicos del Agua , Purificación del Agua , Azul de Metileno/química , Lignina/química , Lignina/análogos & derivados , Ultrafiltración/métodos , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Concentración de Iones de Hidrógeno , Colorantes/química , Colorantes/aislamiento & purificación , Adsorción , Polímeros/químicaRESUMEN
More sustainable materials have been becoming an important concern of worldwide scientists, and cellulosic materials are one alternative in water decontamination. An efficient strategy to improve removal capacity is functionalizing or incorporating nanomaterials in cellulose-based materials. The new hybrid cDAC/ZnONPs was produced by green synthesis of zinc oxide nanoparticles (ZnONPs), promoting the in situ reduction and immobilization on the cationic dialdehyde cellulose microfibers (cDAC) surface to remove Congo red dye from water. cDAC/ZnONPs was characterized by scanning electron microscopy (SEM-EDS) and infrared spectroscopy (FTIR), which showed efficient nanoparticles reduction. Adsorption efficiency on cationic cellulose surface was investigated by pH, contact time, initial concentration, and dye selectivity tests. The material followed the H isotherm model, which resulted in a maximum adsorption capacity of 1091.16 mg/g. Herein, was developed an efficient and ecologically correct new adsorbent, highly effective in Congo red dye adsorption even at high concentrations, suitable for the remediation of contaminated industrial effluents.
Asunto(s)
Rojo Congo , Contaminantes Químicos del Agua , Purificación del Agua , Óxido de Zinc , Óxido de Zinc/química , Rojo Congo/química , Rojo Congo/aislamiento & purificación , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Purificación del Agua/métodos , Tecnología Química Verde , Concentración de Iones de Hidrógeno , Celulosa/química , Celulosa/análogos & derivados , Colorantes/química , Nanopartículas/química , Cinética , Nanopartículas del Metal/química , Celulosa Oxidada/química , Cationes/químicaRESUMEN
Peanut shells' adsorption performance in caffeine and triclosan removal was studied. Peanut shells were analyzed for their chemical composition, morphology, and surface functional groups. Batch adsorption and fixed-bed column experiments were carried out with solutions containing 30 mg/L of caffeine and triclosan. The parameters examined included peanut shell particle size (120-150, 300-600, and 800-2000 µm), adsorbent dose (0.02-60 g/L), contact time (up to 180 min), bed height (4-8 cm), and hydraulic loading rate (2.0 and 4.0 m3/m2-day). After determining the optimal adsorption conditions, kinetics, isotherm, and breakthrough curve models were applied to analyze the experimental data. Peanut shells showed an irregular surface and consisted mainly of polysaccharides (around 70% lignin, cellulose, and hemicellulose), with a specific surface area of 1.7 m2/g and a pore volume of 0.005 cm3/g. The highest removal efficiencies for caffeine (85.6 ± 1.4%) and triclosan (89.3 ± 1.5%) were achieved using the smallest particles and 10.0 and 0.1 g/L doses over 180 and 45 min, respectively. Triclosan showed easier removal compared to caffeine due to its higher lipophilic character. The pseudo-second-order kinetics model provided the best fit with the experimental data, suggesting a chemisorption process between caffeine/triclosan and the adsorbent. Equilibrium data were well-described by the Sips model, with maximum adsorption capacities of 3.3 mg/g and 289.3 mg/g for caffeine and triclosan, respectively. In fixed-bed column adsorption tests, particle size significantly influenced efficiency and hydraulic behavior, with 120-150 µm particles exhibiting the highest adsorption capacity for caffeine (0.72 mg/g) and triclosan (143.44 mg/g), albeit with clogging issues. The experimental data also showed good agreement with the Bohart-Adams, Thomas, and Yoon-Nelson models. Therefore, the findings of this study highlight not only the effective capability of peanut shells to remove caffeine and triclosan but also their versatility as a promising option for water treatment and sanitation applications in different contexts.
Asunto(s)
Arachis , Cafeína , Triclosán , Cafeína/química , Cafeína/aislamiento & purificación , Triclosán/química , Triclosán/aislamiento & purificación , Arachis/química , Adsorción , Cinética , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Tamaño de la Partícula , Purificación del Agua/métodosRESUMEN
Jatobá-do-cerrado fruit shells, archetypical of lignocellulosic-based biomass, were used as an adsorbent to remove crystal violet (CV) and methylene blue (MB) from water. The adsorbent was characterized using various techniques, and kinetic studies showed dye adsorption followed second-order kinetics. An experimental design investigated the effects of pH and temperature on removal efficiency, with a quadratic model fitting the data best. The results suggest pH influences MB's adsorption capacity more than temperature and at 25 °C and pH 8, MB had a desirability value of 0.89, with 95 % removal efficiency. For CV, temperature had a greater influence, with a desirability value of 0.874 at 25 °C and pH 10, and 95 % removal efficiency. Adsorption isotherm studies revealed maximum adsorption capacities of 123.0 mg·g-1 and 113.0 mg·g-1 for CV and MB, respectively. Experimental thermodynamic parameters indicated an endothermic and spontaneous process which it was supported by quantum chemistry calculations. The protocols developed confirmed the potential for adsorbing CV and MB dyes in water, achieving over 73.1 and 74.4 mg g-1 dyes removal.
Asunto(s)
Biomasa , Colorantes , Lignina , Azul de Metileno , Contaminantes Químicos del Agua , Adsorción , Lignina/química , Colorantes/química , Colorantes/aislamiento & purificación , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Concentración de Iones de Hidrógeno , Cinética , Azul de Metileno/química , Azul de Metileno/aislamiento & purificación , Temperatura , Purificación del Agua/métodos , Violeta de Genciana/química , Violeta de Genciana/aislamiento & purificación , Termodinámica , Teoría Funcional de la DensidadRESUMEN
Reducing high concentrations of pollutants such as heavy metals, pesticides, drugs, and dyes from water is an emerging necessity. We evaluated the use of Luffa cylindrica (Lc) as a natural non-conventional adsorbent to remove azo dye mixture (ADM) from water. The capacity of Lc at three different doses (2.5, 5.0, and 10.0 g/L) was evaluated using three concentrations of azo dyes (0.125, 0.250, and 0.500 g/L). The removal percent (R%), maximum adsorption capacity (Qm), isotherm and kinetics adsorption models, and pH influence were evaluated, and Fourier-transform infrared spectroscopy and scanning electron microscopy were performed. The maximum R% was 70.8% for 10.0 g L-1Lc and 0.125 g L-1 ADM. The Qm of Lc was 161.29 mg g-1. Adsorption by Lc obeys a Langmuir isotherm and occurs through the pseudo-second-order kinetic model. Statistical analysis showed that the adsorbent dose, the azo dye concentration, and contact time significantly influenced R% and the adsorption capacity. These findings indicate that Lc could be used as a natural non-conventional adsorbent to reduce ADM in water, and it has a potential application in the pretreatment of wastewaters.
Asunto(s)
Compuestos Azo , Colorantes , Luffa , Contaminantes Químicos del Agua , Purificación del Agua , Luffa/química , Compuestos Azo/química , Compuestos Azo/aislamiento & purificación , Adsorción , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Cinética , Colorantes/química , Concentración de Iones de Hidrógeno , Espectroscopía Infrarroja por Transformada de Fourier , Agua/químicaRESUMEN
A film composed of agarose and graphene (G) and magnetic nanoparticles (G-MNPs) is proposed as a sorbent for the extraction and determination of medroxyprogesterone (MED), levonorgestrel (LEV), norethisterone (NOR) and progesterone (PRO) in natural water samples. Both the preparation of the film and the extraction procedure were optimized. The optimal extraction parameters were as follows: isopropyl alcohol as activation solvent, sample pH value of 3.0, extraction time of 30 min, 1.00 mL of acetonitrile as eluent, elution time of 5 min and sample volume of 100.00 mL. HPLC with photodiode array detector was used for the separation and determination. The method presented a linear range between 2.50 and 75.0 µg L-1 for all analytes, and the LODs were between 1.40 and 1.80 µg L-1. The method was applied to natural water samples, obtaining satisfactory recovery values (75-111 %). In conclusion, for the immobilization of the G-MNPs, agarose was used, which is a non-toxic, renewable and biodegradable material. The G-MNPs-agarose film was reused up to 70 times, without losing its extraction capacity significantly and presenting excellent sorbent properties, which allow the extraction and preconcentration of the progestogens under study.
Asunto(s)
Progestinas , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificación , Contaminantes Químicos del Agua/química , Progestinas/aislamiento & purificación , Progestinas/análisis , Progestinas/química , Adsorción , Nanopartículas de Magnetita/química , Extracción en Fase Sólida/métodos , Sefarosa/química , Cromatografía Líquida de Alta PresiónRESUMEN
In this study, 3D-printing based on fused-deposition modeling (FDM) was employed as simple and cost-effective strategy to fabricate a novel format of rotating-disk sorptive devices. As proof-of-concept, twenty organochlorine and organophosphorus pesticides were determined in water samples through rotating-disk sorptive extraction (RDSE) using honeycomb-like 3D-printed disks followed by gas chromatography coupled to mass spectrometry (GC-MS). The devices that exhibited the best performance were comprised of polyamide + 15 % carbon fiber (PA + 15 % C) with the morphology being evaluated through X-ray microtomography. The optimized extraction conditions consisted of 120 min of extraction using 20 mL of sample at stirring speed of 1100 rpm. Additionally, liquid desorption using 800 µL of acetonitrile for 25 min at stirring speed of 1100 rpm provided the best response. Importantly, the methodology also exhibited high throughput since an extraction/desorption platform that permitted up to fifteen simultaneous extractions was employed. The method was validated, providing coefficients of determination higher than 0.9706 for all analytes; limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.15 to 3.03 µg L-1 and from 0.5 to 10.0 µg L-1, respectively. Intraday precision ranged from 4.01 to 18.73 %, and interday precision varied from 4.83 to 20.00 %. Accuracy was examined through relative recoveries and ranged from 73.29 to 121.51 %. This method was successfully applied to analyze nine groundwater samples from monitoring wells of gas stations in São Paulo. Moreover, the greenness was assessed through AGREEprep metrics, and an overall score of 0.69 was obtained indicating that the method proposed can be considered sustainable.
Asunto(s)
Cromatografía de Gases y Espectrometría de Masas , Hidrocarburos Clorados , Límite de Detección , Compuestos Organofosforados , Plaguicidas , Impresión Tridimensional , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificación , Compuestos Organofosforados/análisis , Compuestos Organofosforados/aislamiento & purificación , Plaguicidas/análisis , Plaguicidas/aislamiento & purificación , Hidrocarburos Clorados/análisis , Hidrocarburos Clorados/aislamiento & purificación , Cromatografía de Gases y Espectrometría de Masas/métodos , AdsorciónRESUMEN
This study focuses on synthesizing and characterizing a graphene oxide/ZnTiO3/TiO2 (GO/ZTO/TO) composite to efficiently remove methylene blue (MB) from water, presenting a novel solution to address industrial dye pollution. GO and ZTO/TO were synthesized by the modified Hummers and sol-gel methods, respectively, while GO/ZTO/TO was prepared using a hydrothermal process. The structural and surface properties of the composite were characterized using various analytical techniques confirming the integration of the constituent materials and suitability for dye adsorption. The study revealed that GO/ZTO/TO exhibits an adsorption capacity of 78 mg g-1 for MB, with only a 15% reduction in adsorption efficiency until the fifth reuse cycle. Furthermore, the study suggests optimal adsorption near neutral pH and enhanced performance at elevated temperatures, indicating an endothermic reaction. The adsorption behavior fits the Langmuir isotherm, implying monolayer adsorption on homogeneous surfaces, and follows pseudo-second-order kinetics, highlighting chemical interactions at the surface as the rate-limiting step. The photocatalytic degradation of MB by GO/ZTO/TO follows pseudo-first-order kinetics, with a higher rate constant than that of GO alone, demonstrating the enhanced photocatalytic activity of the composite. In conclusion, GO/ZTO/TO emerges as a promising and sustainable approach for water purification, through an adsorption process and subsequent photocatalytic degradation.
Asunto(s)
Grafito , Azul de Metileno , Titanio , Contaminantes Químicos del Agua , Purificación del Agua , Azul de Metileno/química , Azul de Metileno/aislamiento & purificación , Titanio/química , Adsorción , Grafito/química , Catálisis , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Cinética , Procesos Fotoquímicos , Concentración de Iones de Hidrógeno , Zinc/químicaRESUMEN
The ubiquity and impact of pharmaceuticals and pesticides, as well as their residues in environmental compartments, particularly in water, have raised human and environmental health concerns. This emphasizes the need of developing sustainable methods for their removal. Solar-driven photocatalytic degradation has emerged as a promising approach for the chemical decontamination of water, sparking intensive scientific research in this field. Advancements in photocatalytic materials have driven the need for solar reactors that efficiently integrate photocatalysts for real-world water treatment. This study reports preliminary results from the development and evaluation of a solar system for TiO2-based photocatalytic degradation of intermittently flowing water contaminated with doxycycline (DXC), sulfamethoxazole (SMX), dexamethasone (DXM), and carbendazim (CBZ). The system consisted of a Fresnel-type UV solar concentrator that focused on the opening and focal point of a parabolic trough concentrator, within which tubular quartz glass reactors were fixed. Concentric springs coated with TiO2, arranged one inside the other, were fixed inside the quartz reactors. The reactors are connected to a raw water tank at the inlet and a check valve at the outlet. Rotating wheels at the collector base enable solar tracking in two axes. The substances (SMX, DXC, and CBZ) were dissolved in dechlorinated tap water at a concentration of 1.0 mg/L, except DXM (0.8 mg/L). The water underwent sequential batch (~ 3 L each, without recirculation) processing with retention times of 15, 30, 60, 90, and 120 min. After 15 min, the degradation rates were as follows: DXC 87%, SMX 35.5%, DXM 32%, and CBZ 31.8%. The system processed 101 L of water daily, simultaneously removing 870, 355, 256, and 318 µg/L of DXC, SMX, DXM, and CBZ, respectively, showcasing its potential for real-world chemical water decontamination application. Further enhancements that enable continuous-flow operation and integrate highly effective adsorbents and photocatalytic materials can significantly enhance system performance.
Asunto(s)
Fotoquímica , Energía Solar , Contaminantes Químicos del Agua , Purificación del Agua , Agua , Catálisis/efectos de la radiación , Agua/química , Purificación del Agua/instrumentación , Purificación del Agua/métodos , Humanos , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Doxiciclina/química , Doxiciclina/aislamiento & purificación , Sulfametoxazol/química , Sulfametoxazol/aislamiento & purificación , Dexametasona/química , Dexametasona/aislamiento & purificación , Cuarzo , Cromatografía , Temperatura , Factores de Tiempo , Animales , Abastecimiento de AguaRESUMEN
This study addresses the limited understanding of chromium-microbial mat interactions in estuarine tidal flats. The aims were to evaluate (1) the efficiency of the microbial consortium in Cr(III) removal from seawater; (2) the elemental and mineralogical composition of the microbial mat as a natural system in the Cr removal, (3) the effects of metal on microphytobenthos, and (4) possible interactions of Cr with other metals present in the consortium. Microbial mats were exposed to Cr(III) solutions at different concentrations (2-30 mg Cr/L). Analysis such as metal concentration, organic matter content, chlorophyll a and phaeopigment concentrations, abundance of diatoms and cyanobacteria, SEM-EDS, and XRD were performed. Most of the Cr(III) was deposited, as chromium oxide/hydroxide, on the surface of all microbial mat components. The complete microbial mat, comprising sediments, detritus, EPS, and diverse microorganism communities, exhibited a remarkable capacity to accumulate Cr(III), retaining over 87% in the solution.
Asunto(s)
Cromo , Microbiota , Agua de Mar , Contaminantes Químicos del Agua , Purificación del Agua , Agua de Mar/química , Cromo/aislamiento & purificación , Contaminantes Químicos del Agua/aislamiento & purificación , Mar Caspio , Purificación del Agua/métodos , Concentración de Iones de Hidrógeno , Fenómenos QuímicosRESUMEN
Purification methods such as membrane technology and adsorption have been studied for the purification of textile effluents. This article aimed to evaluate the membrane separation process and adsorption on pine nut shell, separately and sequentially, for reactive dye blue 5G removal from a synthetic effluent. The membrane separation process was carried out in a front filtration module using polymeric membranes. The maximum dye retention was 35.9% using a regenerated cellulose membrane, with agitation and a pressure of 0.5 bar. The permeate flux was fully restored after cleaning the membrane. In the adsorption using pine nut shell, the best results were at pH 2, 50°C, and 50â ppm, with 85% dye removal. The Freundlich isotherm showed the best fit to the data, as did the pseudo-second-order kinetic model. The thermodynamic parameters indicated that the adsorption is of the physical type, with the process being endothermic and spontaneous. In the combined process, the permeate from the membrane separation process was subjected to adsorption on pine nut shell, achieving a removal rate of 98.7 for the initial concentration of 50â ppm. Therefore, this work shows the potential of pine nut shell as an adsorbent, not only to purify textile effluents but also to add value to a waste product, indicating that the combination of membrane technology and adsorption on pine nut shell could be an alternative for the treatment of textile effluents containing the reactive dye 5G blue.
Asunto(s)
Colorantes , Membranas Artificiales , Nueces , Pinus , Aguas Residuales , Contaminantes Químicos del Agua , Adsorción , Colorantes/química , Colorantes/aislamiento & purificación , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Aguas Residuales/química , Pinus/química , Nueces/química , Purificación del Agua/métodos , Eliminación de Residuos Líquidos/métodosRESUMEN
Antibiotics and pesticides, as well as various emerging contaminants that are present in surface waters, raise significant environmental concerns. Advanced oxidation processes, which are employed to eliminate these substances, have demonstrated remarkable effectiveness. However, during the degradation process, by-products that are not completely mineralized are generated, posing a substantial risk to aquatic ecosystem organisms; therefore, it is crucial to assess effluent ecotoxicity following treatment. This study aimed to assess the toxicity of effluents produced during the removal of amoxicillin and glyphosate with a Fenton-type process using a laminar structure catalyzed with iron (Fe) and copper (Cu). The evaluation included the use of Daphnia magna, Selenastrum capricornutum, and Lactuca sativa, and mutagenicity testing was performed using strains TA98 and TA100 of Salmonella typhimurium. Both treated and untreated effluents exhibited inhibitory effects on root growth in L. sativa, even at low concentrations ranging from 1% to 10% v/v. Similarly, negative impacts on the growth of algal cells of S. capricornutum were observed at concentrations as low as 0.025% v/v, particularly in cases involving amoxicillin-copper (Cu) and glyphosate with copper (Cu) and iron (Fe). Notably, in the case of D. magna, mortality was noticeable even at concentrations of 10% v/v. Additionally, the treatment of amoxicillin with double-layer hydroxides of Fe and Cu resulted in mutagenicity (IM ≥ 2.0), highlighting the necessity to treat the effluent further from the advanced oxidation process to reduce ecological risks.
Asunto(s)
Amoxicilina , Cobre , Glifosato , Contaminantes Químicos del Agua , Amoxicilina/aislamiento & purificación , Catálisis , Cobre/química , Ecotoxicología , Glifosato/aislamiento & purificación , Hierro/química , Contaminantes Químicos del Agua/aislamiento & purificaciónRESUMEN
This study used the bark of the forest species Campomanesia guazumifolia modified with H2SO4 to absorb the anti-inflammatory ketoprofen from aqueous solutions. FTIR spectra confirmed that the main bands remained after the chemical treatment, with the appearance of two new bands related to the elongation of the carbonyl group present in hemicellulose. Micrographs confirmed that the surface started to contain a new textural shape after acid activation, having new pores and cavities. The drug adsorption's optimum conditions were obtained by response surface methodology (RSM). The adsorption was favored at acidic pH (2). The dosage of 1 g L-1 was considered ideal, obtaining good indications of removal and capacity. The Elovich model very well represented the kinetic curves. The isotherm studies indicated that the increase in temperature negatively affected the adsorption of ketoprofen. A maximum adsorption capacity of 158.3 mg g-1 was obtained at the lower temperature of 298 K. Langmuir was the best-fit isotherm. Thermodynamic parameters confirmed the exothermic nature of the system (ΔH0 = -8.78 kJ mol-1). In treating a simulated effluent containing different drugs and salts, the removal values were 35, 50, and 80% at 15, 30, and 180 min, respectively. Therefore, the development of adsorbent from the bark of Campomanesia guazumifolia treated with H2SO4 represents a remarkable alternative for use in effluent treatment containing ketoprofen.
Asunto(s)
Cetoprofeno , Myrtaceae/química , Corteza de la Planta , Contaminantes Químicos del Agua , Adsorción , Sulfuro de Hidrógeno , Concentración de Iones de Hidrógeno , Cetoprofeno/aislamiento & purificación , Cinética , Corteza de la Planta/química , Soluciones , Termodinámica , Contaminantes Químicos del Agua/aislamiento & purificaciónRESUMEN
Biosorption refers to a physicochemical process where substances are removed from the solution by a biological material (live or dead) via adsorption processes governed by mechanisms such as surface complexation, ion exchange, and precipitation. This study aimed to evaluate the adsorption of Zn2+ in seawater using the microalgal biomass of Tetraselmis marina AC16-MESO "in vivo" and "not alive" at different concentrations of Zn2+ (0, 5, 10, and 20 mg L-1) at 72 h. Analysis was carried out by using the Langmuir isotherms and by evaluating the autofluorescence from microalgae. The maximum adsorption of Zn2+ by the Langmuir model using the Qmax parameter in the living microalgal biomass (Qmax = 0.03051 mg g-1) was more significant than the non-living microalgal biomass of T. marine AC16-MESO (Qmax = 0.02297 mg g-1). Furthermore, a decrease in fluorescence was detected in cells from T. marina AC16-MESO, in the following order: Zn2+ (0 < 20 < 5 < 10) mg L-1. Zn2+ was adsorbed quickly by living cells from T. marine AC16-MESO compared to the non-living microalgal biomass, with a decrease in photosystem II activities from 0 to 20 mg L-1 Zn2+ in living cells.
Asunto(s)
Biomasa , Chlorophyta/fisiología , Agua de Mar/química , Contaminantes Químicos del Agua/aislamiento & purificación , Zinc/aislamiento & purificación , Adsorción , Biodegradación Ambiental , Concentración de Iones de Hidrógeno , Contaminantes Químicos del Agua/metabolismo , Zinc/metabolismoRESUMEN
Chemical and thermochemical transformations were performed on orange peel to obtain materials that were characterized and further tested to explore their potential as adsorbents for the removal of methylene blue (MB) from aqueous solutions. The results show the high potential of some of these materials for MB adsorption not only due to the surface area of the resulting substrate but also to the chemistry of the corresponding surface functional groups. Fitting of the kinetic as well as the equilibrium experimental data to different models suggests that a variety of interactions are involved in MB adsorption. The overall capacities for these substrates (larger than 192.31 mg g-1) were found to compare well with those reported for activated carbon and other adsorbents of agro-industrial origin. According to these results and complementary with theoretical study using Density Functional Theory (DFT) approximations, it was found that the most important adsorption mechanisms of MB correspond to: (i) electrostatic interactions, (ii) H-bonding, and (iii) π (MB)-π (biochar) interactions. In view of these findings, it can be concluded that adsorbent materials obtained from orange peel, constitute a good alternative for the removal of MB dye from aqueous solutions.
Asunto(s)
Citrus sinensis/química , Frutas/química , Azul de Metileno/aislamiento & purificación , Aguas Residuales/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Carbón Orgánico/química , Teoría Funcional de la Densidad , Humanos , Enlace de Hidrógeno , Concentración de Iones de Hidrógeno , Cinética , Polvos , Electricidad Estática , Residuos/análisisRESUMEN
An on-line solid phase extraction using a lab-made restricted access media (RAM) was developed as sample preparation procedure for determination of the pharmaceutical compounds caffeine (CAF), carbamazepine (CBZ), norfloxacin (NOR), ciprofloxacin (CIP), fluoxetine (FLX) and venlafaxine in wastewater treatment plant samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method is suitable for use in routine of analysis, avoiding cross-contamination and requiring only a small sample volume (50 µL), with minimal handling. The method was validated according to international guidelines. The chromatographic efficiency was evaluated using peak resolution and asymmetry parameters. Carryover was also evaluated, in order to ensure reliability of the analysis and the ability to reuse the cartridge. Satisfactory linearity (r2 > 0.99) was obtained for all the compounds. The intra- and inter-day precision values were lower than 5.79 and 14.1%, respectively. The limits of detection ranged from 0.01 to 3 µg L-1 and the limits of quantification were from 0.1 to 5 µg L-1. The method was applied to 20 environmental wastewater samples, with caffeine being the most widely detected compound, at the highest concentration of 392 µg L-1, while other compounds were detected in fewer samples at lower concentrations (up to 9.60 µg L-1). The lab-made modification is a cheaper option for on-line sample preparation, compared to commercially available on-line SPE cartridges and RAM columns. Moreover, a high-throughput procedure was achieved, with an analysis time of 16 min including sample preparation and chromatographic separation. The same RAM column was applied over 200 injections including method optimization, validation and application in wastewater samples without loss of analytical response.